As shown in FIG. 1, a prior art modular rack comprises a plurality of upright support rods A1 and shelves A2 which are supported by the upright support rods A1 in conjunction with a plurality of locating pieces A3 and sleeves A21. Each of the upright support rods A1 is provided in the outer surface thereof with a plurality of locating grooves A11 which are arranged at an interval. The locating pieces A3 are provided in the inner wall thereof with a locating rib A31. The locating pieces A3 are located in pair on the upright support rods A1 such that the locating ribs A31 are retained in the locating grooves. Each shelf A2 is provided at four comers thereof with four sleeves A21 and is supported by the upright support rods A1 such that each of the four sleeves A21 is fitted over the locating pieces A3.
Such a prior art modular rack as described above is defective in design in that the entire rack must be dismantled to rearrange the shelves A2, and that the sleeves A21 of the shelves A2 can not be easily separated from the locating pieces A3.